MVME3100 FPU Support on RTEMS 4.10.2

[Matt Rippa]

Thanks for the fast reply. Of all the mvme boards you listed,
the 3100 hits a nice price point and we're attempting to find
suitable replacement stock
​(quantity 30+) ​
for the 2700 which are no longer
manufactured.
​ ​

Are the 6100 boards on beatnik bsp the only remaining option for RTEMS?
They cost nearly twice as much and have
​shown ​
thermal regulation issues.

-Matt

On Wed, Jun 6, 2018 at 11:10 AM, Michael Davidsaver <
mdavidsaver at ospreydcs.com> wrote:

> Hi Matt,
>
> The MVME3100 is based on the MPC8540 processor.  This chip doesn't have an
> FPU.
> Other boards do (eg. mvme270x, mvme6100, or mvme2500) and RTEMS supports
> this.
>
> I can certainly confirm that lack of an FPU really hurts performance, even
> something as (apparently) simple as integer to float.
>
> Michael
>
>
> On 06/06/2018 02:03 PM, Matt Rippa wrote:
> > It appears we've compiled our mvme3100 bsp without FPU support.
> > We're on the mvme3100 running EPICS 3.14.12.7 and RTEMS 4.10.2.
> >
> > We're attempting to commission our astrometric kernel control system
> > and we've run into trouble meeting some of our thread deadlines. What
> > we've found is a transform routine that takes our mvme2700 ~200 us,
> > takes the mvme3100 ~8 ms.  So not a surprise to see this with only
> "-msoft-float"?
> >
> > ...
> > 2018-05-31-tcs.log:May 31 11:41:15  E) PORT: tcs_vme, MSG: Welcome to
> rtems-4.10.2(PowerPC/Generic (*no FPU*)/mvme3100)
> >
> > Is FPU support possible with RTEMS 4.10.2? If so, what would we need to
> do?
> > It looks like there's a multilib on 4.11.2 https://docs.rtems.org/
> releases/rtems-docs-4.11.2/cpu-supplement/powerpc.html#multilibs(*Eg.,
> see #13* )
> >
> > Here's our bsp specs:
> >
> > beatnik:
> > -specs bsp_specs -qrtems -fasm -c -mcpu=7400 -D__ppc_generic -DUNIX -O2
> -g -g -Wall
> > (mvme2700) mvme-2307:
> > -specs bsp_specs -qrtems -fasm -c -mcpu=604 -mmultiple -mstring
> -mstrict-align -meabi -DUNIX -O2 -g -g -Wall
> > mvme-3100
> > -specs bsp_specs -qrtems -fasm -c -mcpu=powerpc *-msoft-float*
> -D__ppc_generic -DUNIX -O2 -g -g -Wall
> >
> > Thank you!
> > -Matt
> >
>



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